High temperature RF heater pedestals

ABSTRACT

Semiconductor processing systems are described, which may include a substrate support assembly having a substrate support surface. Exemplary substrate support assemblies may include a ceramic heater defining the substrate support surface. The assemblies may include a ground plate on which the ceramic heater is seated. The assemblies may include a stem with which the ground plate is coupled. The assemblies may include an electrode embedded within the ceramic heater at a depth from the substrate support surface. The chambers or systems may also include an RF match configured to provide an AC current and an RF power through the stem to the electrode. The RF match may be coupled with the substrate support assembly along the stem. The substrate support assembly and RF match may be vertically translatable within the semiconductor processing system.

TECHNICAL FIELD

The present technology relates to components and apparatuses forsemiconductor manufacturing. More specifically, the present technologyrelates to substrate pedestal assemblies and other semiconductorprocessing equipment.

BACKGROUND

Integrated circuits are made possible by processes which produceintricately patterned material layers on substrate surfaces. Producingpatterned material on a substrate requires controlled methods forforming and removing material. The temperature at which these processesoccur may directly impact the final product. Substrate temperatures areoften controlled and maintained with the assembly supporting thesubstrate during processing. Additionally, substrate-level plasmas maybe formed to produce radical effluents that may be used in substrateprocessing. As substrate processing becomes more intricate, many plasmaoperations occur at power levels that damage structures, and may notprovide sufficient control over plasma characteristics leading tovariation in the performance. Depending on the degree of variation,processes may not be performed uniformly across a substrate surface, anddevice failure may occur due to the inconsistencies produced by theapplications.

Additionally, the structures housed within a semiconductor processingchamber may be affected by the processes performed within the chamber.For example, plasma effluents produced within a chamber may bombard orotherwise interact with other chamber components, which may lead tocorrosion or erosion.

Thus, for these and other reasons, there is a need for improvedequipment and assemblies within semiconductor processing chambers. Theseand other needs are addressed by the present technology.

SUMMARY

Semiconductor processing systems are described, which may include asubstrate support assembly having a substrate support surface. Exemplarysubstrate support assemblies may include a ceramic heater defining thesubstrate support surface. The assemblies may include a ground plate onwhich the ceramic heater is seated. The assemblies may include a stemwith which the ground plate is coupled. The assemblies may include anelectrode embedded within the ceramic heater at a depth from thesubstrate support surface. The chambers or systems may also include anRF match configured to provide an AC current and an RF power through thestem to the electrode. The RF match may be coupled with the substratesupport assembly along the stem. The substrate support assembly and RFmatch may be vertically translatable within the semiconductor processingsystem.

In some embodiments, the depth from the substrate support surface atwhich the electrode is embedded in the ceramic heater may be less thanor about 5 mm. The substrate support assembly may be configured to heata substrate to a temperature greater than or about 200° C. The substratesupport surface may be coated with a plasma resistant materialcomprising yttrium oxide. The processing system may further include anRF rod extending between the RF match and the substrate supportassembly. The processing system may further include a second RF rodpositioned within a ceramic shaft disposed within the stem and diffusionbonded with the ceramic heater. The substrate support assembly mayinclude fewer than ten couplings between the RF rod and the electrode.The RF match may include an RF strap coupling an RF power source withthe RF rod. The RF match may include an RF filter coupling an AC powersource with the RF rod. The RF filter may include an inductor and acapacitor. The inductor may be or include a ferrite core. The inductormay provide at least 2 μH of inductance. The RF match may be configuredto provide a pulsing RF power. The electrode may be configured togenerate an RF bias plasma in a volume within the semiconductorprocessing system above the substrate support assembly.

Some embodiments of the present technology may also encompass substratesupport assemblies having a substrate support surface. The substratesupport assembly may include a ceramic heater defining the substratesupport surface. The substrate support assembly may include a groundplate on which the ceramic heater is seated. The substrate supportassembly may include a stem with which the ground plate is coupled. Thesubstrate support assembly may include an electrode embedded within theceramic heater at a depth from the substrate support surface. Theelectrode may be configured to generate an RF bias plasma in a volumeabove the substrate support assembly. The substrate support assembly mayalso include an RF match configured to provide an AC current and an RFpower through the stem to the electrode.

In some embodiments, the RF match may be configured to provide a plasmapower of below or about 100 W to the electrode. The RF match may includean RF strap coupling an RF power source with an RF rod extending betweenthe RF match and the substrate support assembly. The RF match mayinclude an RF filter coupling an AC power source with the RF rod. The RFfilter may include an inductor and a capacitor. The substrate supportassembly may be configured to heat a substrate to a temperature greaterthan or about 400° C.

Some embodiments of the present technology may also encompasssemiconductor processing systems. The systems may include a substratesupport assembly having a substrate support surface. The substratesupport assembly may include a ceramic heater defining the substratesupport surface. The substrate support assembly may include a groundplate on which the ceramic heater is seated. The substrate supportassembly may include a stem with which the ground plate is coupled. Thesubstrate support assembly may also include an electrode embedded withinthe ceramic heater at a depth from the substrate support surface. Theelectrode may be configured to generate an RF bias plasma in a volumeabove the substrate support assembly. The systems may also include an RFmatch configured to provide an AC current and an RF power through thestem to the electrode. The RF match may be coupled with the substratesupport assembly along the stem. The RF match may be configured toprovide a plasma power of below or about 50 W to the electrode.Electrical couplings between the RF match and the electrode may becharacterized by losses in operation of less than or about 1 W. Thesubstrate support assembly and RF match may be vertically translatablewithin the semiconductor processing system.

Such technology may provide numerous benefits over conventionalequipment. For example, assemblies according to some embodiments of thepresent technology may be capable of operation at higher temperaturesthan conventional devices. Additionally, the systems of the presenttechnology may produce stable plasmas at low power, providing increasedcontrol over conventional devices. These and other embodiments, alongwith many of their advantages and features, are described in more detailin conjunction with the below description and attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the disclosedembodiments may be realized by reference to the remaining portions ofthe specification and the drawings.

FIG. 1 shows a top plan view of one embodiment of an exemplaryprocessing tool according to some embodiments of the present technology.

FIG. 2A shows a schematic cross-sectional view of one embodiment of aprocessing chamber in which a pedestal according to some embodiments ofthe present technology may be found.

FIG. 2B shows a detailed view of a portion of the processing chamberillustrated in FIG. 2A according to some embodiments of the presenttechnology.

FIG. 3 shows a bottom plan view of an exemplary showerhead according toembodiments of the present technology.

FIG. 4 illustrates a perspective cross-sectional schematic view of asubstrate support assembly according to some embodiments of the presenttechnology.

FIG. 5 illustrates a cross-sectional schematic view of a substratesupport assembly according to some embodiments of the presenttechnology.

FIG. 6 shows a partial cross-sectional schematic view of a substratesupport assembly according to some embodiments of the presenttechnology.

FIG. 7 illustrates a schematic view of an RF match according to someembodiments of the present technology.

FIG. 8 illustrates a schematic view of an RF match according to someembodiments of the present technology.

FIG. 9 illustrates a schematic view of an RF match according to someembodiments of the present technology.

Several of the figures are included as schematics. It is to beunderstood that the figures are for illustrative purposes, and are notto be considered of scale unless specifically stated to be of scale.Additionally, as schematics, the figures are provided to aidcomprehension and may not include all aspects or information compared torealistic representations, and may include additional or exaggeratedmaterial for illustrative purposes.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a letter thatdistinguishes among the similar components. If only the first referencelabel is used in the specification, the description is applicable to anyone of the similar components having the same first reference labelirrespective of the letter.

DETAILED DESCRIPTION

As device features continue to reduce in size and increase in intricacy,controlled removal of material is becoming increasingly important. Onemethod of removal involves removing thin layers of material sequentiallyin multi-part etch processes. Once such etch process may includemodifying a surface of a feature or material to be removed by contactingthe material with inert plasma effluents, which may damage bonding ofthe material, and may facilitate removal in a subsequent chemicalprocess, which may be performed at high temperature. The modificationoperation may include forming a wafer or substrate-level plasma thatallows bombardment of exposed features and materials. Some processes areused to remove thin layers of material, such as Angstroms or nanometersof material, and thus control and minimized removal may be sought.

Many conventional plasma systems are not capable of producingcontrolled, low-level bias plasma at the substrate level utilizing apedestal or substrate support as a hot electrode. Due to limitations onplasma sources and matching circuits, the technologies cannotconsistently and sufficiently sustain plasma at low power. The complexcouplings and systems may produce losses that are too great for lowpower plasma. Additionally, the same couplings and materials may be usedto deliver current for a resistive heater on or within the pedestalassembly. The current components may have interference from the plasmapower, and further losses may occur. Additionally, depending on thepedestal configuration, coupling within the pedestal may not allowoperation at high temperature, which may damage bonding on a chuck.

Embodiments of the present technology overcome these and other issues byutilizing specific components and configurations that may minimizecoupling within the pedestal. Additionally, incorporating additionalfilters in the RF match may reduce noise, further reducing losses andinterference. Finally, materials utilized in the pedestal may includematerials selected to limit interface bonding damage that may otherwiseoccur in higher temperature operating conditions. After describing anexemplary system in which pedestals according to some embodiments of thepresent technology may be disposed, the disclosure will describe anumber of features of various substrate support assemblies.

FIG. 1 shows a top plan view of one embodiment of a processing system100 of deposition, etching, baking, and curing chambers according toembodiments. In the figure, a pair of front opening unified pods (FOUPs)102 supply substrates of a variety of sizes that are received by roboticarms 104 and placed into a low pressure holding area 106 before beingplaced into one of the substrate processing chambers 108 a-f, positionedin tandem sections 109 a-c. A second robotic arm 110 may be used totransport the substrate wafers from the holding area 106 to thesubstrate processing chambers 108 a-f and back. Each substrateprocessing chamber 108 a-f, can be outfitted to perform a number ofsubstrate processing operations including the dry etch processesdescribed herein in addition to cyclical layer deposition (CLD), atomiclayer deposition (ALD), chemical vapor deposition (CVD), physical vapordeposition (PVD), etch, pre-clean, degas, orientation, and othersubstrate processes.

The substrate processing chambers 108 a-f may include one or more systemcomponents for depositing, annealing, curing and/or etching a dielectricfilm on the substrate wafer. In one configuration, two pairs of theprocessing chambers, e.g., 108 c-d and 108 e-f, may be used to depositdielectric material on the substrate, and the third pair of processingchambers, e.g., 108 a-b, may be used to etch the deposited dielectric.In another configuration, all three pairs of chambers, e.g., 108 a-f,may be configured to etch a dielectric film on the substrate. Any one ormore of the processes described may be carried out in chamber(s)separated from the fabrication system shown in different embodiments. Itwill be appreciated that additional configurations of deposition,etching, annealing, and curing chambers for dielectric films arecontemplated by system 100.

FIG. 2A shows a cross-sectional view of an exemplary process chambersystem 200 with partitioned plasma generation regions within theprocessing chamber. During film etching, e.g., titanium nitride,tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, siliconnitride, silicon oxynitride, silicon oxycarbide, etc., a process gas maybe flowed into the first plasma region 215 through a gas inlet assembly205. A remote plasma system (RPS) 201 may optionally be included in thesystem, and may process a first gas which then travels through gas inletassembly 205. The inlet assembly 205 may include two or more distinctgas supply channels where the second channel (not shown) may bypass theRPS 201, if included.

A cooling plate 203, faceplate 217, ion suppressor 223, showerhead 225,and a substrate support 265, having a substrate 255 disposed thereon,are shown and may each be included according to embodiments. Thepedestal 265 may have a heat exchange channel through which a heatexchange fluid flows to control the temperature of the substrate, whichmay be operated to heat and/or cool the substrate or wafer duringprocessing operations. The wafer support platter of the pedestal 265,which may comprise aluminum, ceramic, or a combination thereof, may alsobe resistively heated in order to achieve relatively high temperatures,such as from up to or about 100° C. to above or about 1100° C., using anembedded resistive heater element.

The faceplate 217 may be pyramidal, conical, or of another similarstructure with a narrow top portion expanding to a wide bottom portion.The faceplate 217 may additionally be flat as shown and include aplurality of through-channels used to distribute process gases. Plasmagenerating gases and/or plasma excited species, depending on use of theRPS 201, may pass through a plurality of holes, shown in FIG. 2B, infaceplate 217 for a more uniform delivery into the first plasma region215.

Exemplary configurations may include having the gas inlet assembly 205open into a gas supply region 258 partitioned from the first plasmaregion 215 by faceplate 217 so that the gases/species flow through theholes in the faceplate 217 into the first plasma region 215. Structuraland operational features may be selected to prevent significant backflowof plasma from the first plasma region 215 back into the supply region258, gas inlet assembly 205, and fluid supply system 210. The faceplate217, or a conductive top portion of the chamber, and showerhead 225 areshown with an insulating ring 220 located between the features, whichallows an AC potential to be applied to the faceplate 217 relative toshowerhead 225 and/or ion suppressor 223. The insulating ring 220 may bepositioned between the faceplate 217 and the showerhead 225 and/or ionsuppressor 223 enabling a capacitively coupled plasma (CCP) to be formedin the first plasma region. A baffle (not shown) may additionally belocated in the first plasma region 215, or otherwise coupled with gasinlet assembly 205, to affect the flow of fluid into the region throughgas inlet assembly 205.

The ion suppressor 223 may comprise a plate or other geometry thatdefines a plurality of apertures throughout the structure that areconfigured to suppress the migration of ionically-charged species out ofthe first plasma region 215 while allowing uncharged neutral or radicalspecies to pass through the ion suppressor 223 into an activated gasdelivery region between the suppressor and the showerhead. Inembodiments, the ion suppressor 223 may comprise a perforated plate witha variety of aperture configurations. These uncharged species mayinclude highly reactive species that are transported with less reactivecarrier gas through the apertures. As noted above, the migration ofionic species through the holes may be reduced, and in some instancescompletely suppressed. Controlling the amount of ionic species passingthrough the ion suppressor 223 may advantageously provide increasedcontrol over the gas mixture brought into contact with the underlyingwafer substrate, which in turn may increase control of the depositionand/or etch characteristics of the gas mixture. For example, adjustmentsin the ion concentration of the gas mixture can significantly alter itsetch selectivity, e.g., SiNx:SiOx etch ratios, Si:SiOx etch ratios, etc.In alternative embodiments in which deposition is performed, it can alsoshift the balance of conformal-to-flowable style depositions fordielectric materials.

The plurality of apertures in the ion suppressor 223 may be configuredto control the passage of the activated gas, i.e., the ionic, radical,and/or neutral species, through the ion suppressor 223. For example, theaspect ratio of the holes, or the hole diameter to length, and/or thegeometry of the holes may be controlled so that the flow ofionically-charged species in the activated gas passing through the ionsuppressor 223 is reduced. The holes in the ion suppressor 223 mayinclude a tapered portion that faces the plasma excitation region 215,and a cylindrical portion that faces the showerhead 225. The cylindricalportion may be shaped and dimensioned to control the flow of ionicspecies passing to the showerhead 225. An adjustable electrical bias mayalso be applied to the ion suppressor 223 as an additional means tocontrol the flow of ionic species through the suppressor.

The ion suppressor 223 may function to reduce or eliminate the amount ofionically charged species traveling from the plasma generation region tothe substrate. Uncharged neutral and radical species may still passthrough the openings in the ion suppressor to react with the substrate.It should be noted that the complete elimination of ionically chargedspecies in the reaction region surrounding the substrate may not beperformed in embodiments. In certain instances, ionic species areintended to reach the substrate in order to perform the etch and/ordeposition process. In these instances, the ion suppressor may help tocontrol the concentration of ionic species in the reaction region at alevel that assists the process.

Showerhead 225 in combination with ion suppressor 223 may allow a plasmapresent in first plasma region 215 to avoid directly exciting gases insubstrate processing region 233, while still allowing excited species totravel from chamber plasma region 215 into substrate processing region233. In this way, the chamber may be configured to prevent the plasmafrom contacting a substrate 255 being etched. This may advantageouslyprotect a variety of intricate structures and films patterned on thesubstrate, which may be damaged, dislocated, or otherwise warped ifdirectly contacted by a generated plasma. Additionally, when plasma isallowed to contact the substrate or approach the substrate level, therate at which oxide species etch may increase. Accordingly, if anexposed region of material is oxide, this material may be furtherprotected by maintaining the plasma remotely from the substrate.

The processing system may further include a power supply 240electrically coupled with the processing chamber to provide electricpower to the faceplate 217, ion suppressor 223, showerhead 225, and/orpedestal 265 to generate a plasma in the first plasma region 215 orprocessing region 233. The power supply may be configured to deliver anadjustable amount of power to the chamber depending on the processperformed. Such a configuration may allow for a tunable plasma to beused in the processes being performed. Unlike a remote plasma unit,which is often presented with on or off functionality, a tunable plasmamay be configured to deliver a specific amount of power to the plasmaregion 215. This in turn may allow development of particular plasmacharacteristics such that precursors may be dissociated in specific waysto enhance the etching profiles produced by these precursors.

A plasma may be ignited either in chamber plasma region 215 aboveshowerhead 225 or substrate processing region 233 below showerhead 225.Plasma may be present in chamber plasma region 215 to produce theradical precursors from an inflow of, for example, a fluorine-containingprecursor or other precursor. An AC voltage typically in the radiofrequency (RF) range may be applied between the conductive top portionof the processing chamber, such as faceplate 217, and showerhead 225and/or ion suppressor 223 to ignite a plasma in chamber plasma region215 during deposition. An RF power supply may generate a high RFfrequency of 13.56 MHz but may also generate other frequencies alone orin combination with the 13.56 MHz frequency.

FIG. 2B shows a detailed view 253 of the features affecting theprocessing gas distribution through faceplate 217. As shown in FIGS. 2Aand 2B, faceplate 217, cooling plate 203, and gas inlet assembly 205intersect to define a gas supply region 258 into which process gases maybe delivered from gas inlet 205. The gases may fill the gas supplyregion 258 and flow to first plasma region 215 through apertures 259 infaceplate 217. The apertures 259 may be configured to direct flow in asubstantially unidirectional manner such that process gases may flowinto processing region 233, but may be partially or fully prevented frombackflow into the gas supply region 258 after traversing the faceplate217.

The gas distribution assemblies such as showerhead 225 for use in theprocessing chamber section 200 may be referred to as dual channelshowerheads (DCSH) and are additionally detailed in the embodimentsdescribed in FIG. 3. The dual channel showerhead may provide for etchingprocesses that allow for separation of etchants outside of theprocessing region 233 to provide limited interaction with chambercomponents and each other prior to being delivered into the processingregion.

The showerhead 225 may comprise an upper plate 214 and a lower plate216. The plates may be coupled with one another to define a volume 218between the plates. The coupling of the plates may be so as to providefirst fluid channels 219 through the upper and lower plates, and secondfluid channels 221 through the lower plate 216. The formed channels maybe configured to provide fluid access from the volume 218 through thelower plate 216 via second fluid channels 221 alone, and the first fluidchannels 219 may be fluidly isolated from the volume 218 between theplates and the second fluid channels 221. The volume 218 may be fluidlyaccessible through a side of the gas distribution assembly 225.

FIG. 3 is a bottom view of a showerhead 325 for use with a processingchamber according to embodiments. Showerhead 325 may correspond with theshowerhead 225 shown in FIG. 2A. Through-holes 365, which show a view offirst fluid channels 219, may have a plurality of shapes andconfigurations in order to control and affect the flow of precursorsthrough the showerhead 225. Small holes 375, which show a view of secondfluid channels 221, may be distributed substantially evenly over thesurface of the showerhead, even amongst the through-holes 365, and mayhelp to provide more even mixing of the precursors as they exit theshowerhead than other configurations.

The chamber discussed previously, along with any other chamber in whichplasma or non-plasma operations may be performed, may include additionalsubstrate support assemblies that may be used in performing exemplarymethods including etching methods as previously described. Turning toFIG. 4 is illustrated a perspective cross-sectional view of a substratesupport assembly 400 according to some embodiments of the presenttechnology. The support assembly 400 may include a substrate support 405and a stem 410. The substrate support 405 may define a substrate supportsurface 407 that is configured to support a substrate during asemiconductor processing operation. The substrate support surface 407may be made from a metal, such as aluminum, or a ceramic or othermaterial, and may be treated or coated with other materials that provideimproved corrosion resistance, improved contact with the substrate, orreduced erosion from plasma effluents, for example.

The stem 410 may be attached to the substrate support 405 opposite thesubstrate support surface 407. The stem 410 may include one or moreinternal channels 412 configured to deliver and receive temperaturecontrolled fluids, pressurized fluids, gases, as well as to provide aconduit for components including thermocouples, rods, and otherconnective items. The substrate support may include multiple components,and may include a heater plate 415, which may be a ceramic heater or anyother type of conductive material. The heater plate 415 may include anembedded electrode, which will be described further below, and which mayreceive current for temperature control of heater 415. Additionally, thesubstrate support may include a ground plate 417 on which the heaterplate 415 may be positioned. Ground plate 417 may be coupled with thestem 410, and may be electrically isolated from the electrode embeddedwithin the heater plate. For example, because current may be deliveredto the electrode, heater 415, which may be ceramic as noted previously,may operate as an insulator to limit shorting from the electrode.

Part of stem 410 may be threaded, or may include a screw thread profile413, which may allow substrate support assembly 400 to be translatedvertically up and down with a motorized and similarly threaded mechanism414. Providing vertical translation may afford a number of benefits byallowing a reduction in the gap between the pedestal and an opposingelectrode defining the plasma processing region. By adjusting the plasmawindow, more control may be afforded during processing. Manyconventional support assemblies, especially those with RF plasmacapabilities, may be fixed in position, and are not amenable tomovement, which may require additional coupling, or may not be practicalbased on separately positioned plasma components requiring fixedcoupling, such as the RF match. The present technology allows anadjustable plasma window by coupling many associated components with themoveable pedestal. These devices may move along with the pedestalitself, which may allow movement of otherwise fixed components.

Substrate support assembly 400 may additionally include an RF match 420,which may be coupled with a portion of the stem 410, such as below achamber bottom 403 through which the substrate support assembly extends.RF match 420 is shown empty in this figure, but components included inthe RF match will be described in further detail below. RF match 420 mayoperate as an impedance matching network for the RF power delivered.Typically, a matching network may be connected between a source and aload, which may be the electrode embedded within the ceramic heater. Thecircuitry may be designed and configured to transfer as much power aspossible to the load while showing an input impedance that is equal tothe complex conjugate of the output impedance of the source, such as 50ohm, for example. In low-power systems, improving the RF match mayimprove stability of the plasma produced, and may reduce interferencewith other sources presented through the constituent components. RFmatch 420 may be configured to provide RF power to the embeddedelectrode. In some embodiments, RF match 420 may also provide current,such as AC current, for operating a resistive heating element, which mayalso be the electrode embedded within the ceramic heater. Designs andconfigurations of RF match 420 will be described in further detailbelow.

RF match 420 may provide AC current and/or RF power through the stem 410to the electrode embedded within the heater plate 415. The RF match 420may be coupled with the substrate support assembly as shown, and may bedirectly coupled to the stem. Accordingly, the match may move with thepedestal assembly, allowing vertical translation of the pedestal withoutcomplicating the RF path through the assembly. An RF generator, notshown, may be connected to the RF match for providing RF power at avariety of operating frequencies from about 400 kHz to about 60 MHz, andwhich may include 400 kHz, 2 MHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, aswell as any other included frequency, including any narrower frequencyranges encompassed within the broader range. RF match 420 may beconfigured to operate or provide a certain plasma power, which may bespecifically a low-power plasma in some embodiments. For example, a 5 kWRF match may not be capable of producing a stable plasma of 5 W, whileRF matches according to embodiments of the present technology may beconfigured to produce stable plasma at low power.

For example, RF match 420 according to embodiments of the presenttechnology may be configured to operate with an RF plasma power of lessthan or about 1 kW, and may be specifically configured to operate withan RF plasma power of less than or about 500 W, less than or about 100W, less than or about 90 W, less than or about 80 W, less than or about70 W, less than or about 60 W, less than or about 50 W, less than orabout 40 W, less than or about 30 W, less than or about 20 W, less thanor about 10 W, less than or about 9 W, less than or about 8 W, less thanor about 7 W, less than or about 6 W, less than or about 5 W, less thanor about 4 W, less than or about 3 W, or less. For example, in someembodiments based on reduced losses and control over the plasma windowwithin the chamber due to the vertical translation capabilities, RFmatches according to the present technology may produce stable plasma ina range between or about 5 W and about 100 W in embodiments of thepresent technology. When lower level power plasmas are produced, such aslocal plasmas, less structural damage may occur across features of asubstrate, and more fine tune removal may be provided. For example, thelower power may limit ion penetration at the substrate surfaces, whichmay limit damage and the depth of removal.

The coupling between the RF match 420 and the embedded electrode mayinclude a number of components and couplings providing an RF powerdelivery path through the pedestal. However, in some embodiments, thecomponents and path may be specified to reduce couplings, turns, andother sources of loss within the system. A first RF rod 425 may bepositioned within RF match 420 and assembly stem 410, and may extendbetween the RF match 420 and the pedestal. First RF rod 425 may couplewith a beam rod 430, which may be a coupling or other connectivestructure that may provide direct or indirect coupling between first RFrod 425, including between an interstitial component coupled with firstRF rod 425, and a second RF rod 435. Second RF rod 435 may extendthrough the stem and into the substrate support 405, where the second RFrod 435 may couple with the electrode embedded within the heater plate415. In some embodiments, second RF rod 435 may extend rigidly upthrough the stem, and may be a single or multi-piece component. Any ofthe components may be conductive and intended to minimize losses throughthe system.

As noted above, in low-power plasma systems, losses may be dramatic. Forexample, in a 3 kW system, losses that account for 1 W of loss may beexceptional as less than a 1% loss. However, in a system providing a 5 Wplasma power, 1 W of loss from couplings and materials is a 20% loss,which may limit stability of the plasma, and may cause a number ofperformance issues. Couplings, connections, and materials may eachcontribute to losses, as well as other interference, which will bediscussed further below. In some embodiments, systems according to thepresent technology may have fewer than 10 couplings between the RFgenerator and the electrode incorporated within the pedestal andoperating to generate a plasma within the processing region of thechamber in a volume above the substrate support surface.

The couplings may include couplings through the RF match, or may includethe number of couplings between the match at RF rod 425 and theelectrode within the substrate support. Additionally, the systems or anyof these positions may include less than or about 9 couplings, less thanor about 8 couplings, less than or about 7 couplings, less than or about6 couplings, less than or about 5 couplings, less than or about 4couplings, less than or about 3 couplings, or less than or about 2couplings, in which the generator or RF match may include a singleelement coupled with the electrode. Materials utilized for the RF rodsor any couplings may include copper, aluminum, silver, gold, which mayinclude plating one of these materials on less expensive materials.Additionally, cable utilized in the system may be 50 ohm coaxial cable.The number of turns from the RF match to the electrode may also affectlosses where increased turns may increase losses, and in someembodiments, RF delivery paths may be characterized by less than orabout 10 turns from one component to the next in the delivery path, andmay be characterized by less than or about 9 turns, less than or about 8turns, less than or about 7 turns, less than or about 6 turns, less thanor about 5 turns, less than or about 4 turns, less than or about 3turns, less than or about 2 turns, less than or about 1 turns, or noturns in some embodiments.

In combination, these materials, along with a filter as will bedescribed below, may combine to limit losses within the system. Thelosses may be relative to the power output for the RF plasma. Forexample, 1 W of loss may represent a 1% loss in a 100 W plasmaconfiguration, but may represent a 20% loss in a 5 W plasmaconfiguration. Accordingly, the present technology may produce losses inoperation of less than or about 10 W regardless of the plasma power, andmay produce losses of less than or about 9 W, less than or about 8 W,less than or about 7 W, less than or about 6 W, less than or about 5 W,less than or about 4 W, less than or about 3 W, less than or about 2 W,less than or about 1 W, or less. Similarly, and based on a particularplasma power at which the RF match is being operated, the system may beconfigured to provide losses in operation of less than or about 20%, andmay provide losses of less than or about 18%, less than or about 16%,less than or about 14%, less than or about 12%, less than or about 10%,less than or about 9%, less than or about 8%, less than or about 7%,less than or about 6%, less than or about 5%, less than or about 4%,less than or about 3%, less than or about 2%, less than or about 1%, orless.

FIG. 5 illustrates a partial cross-sectional view of substrate supportassembly 400 according to some embodiments of the present technology. Asillustrated, the assembly may include a substrate support 405 and a stem410. A ground plate 417 may be coupled with the stem. As illustrated, agap may be formed between ground plate 417 and the heater plate 415 tolimit shorting between the components. The figure also illustrates anumber of channels that may be formed within stem 410. Channels 412 amay provide communication for pathways, such as purge gas or otherfluidic passages including vacuum chucking, and which may be coupledwith the substrate support. Additionally, channel 412 b may be includedto provide coupling with the heater plate 415, which may be ceramic, andthe second RF rod 435, which may be coupled with the embedded electrode.A thermocouple 440 may also be incorporated within the pedestal toprovide accurate temperature measurements during operation.

As previously stated, the present substrate support assembly may beconfigured to allow high temperature heating of a substrate. Manyconventional pedestals utilize silicon bonding for certain connectionson an electrostatic chuck, or other substrate support. This siliconbonding typically degrades at temperatures above about 200° C.Embodiments of the present technology may include no silicon bondingwithin the substrate support, and may include diffusion bonding betweenthe components. For example, heater plate 415 may be a ceramic heater,such as a ceramic plate. Although any coupling may be used, in someembodiments channel 412 b may be a ceramic shaft through which thesecond RF rod 435 may be disposed. Channel 412 b may include a diffusionbond with heater plate 415, producing a bond configured to withstandhigh temperature processing. Accordingly, pedestals according toembodiments of the present technology may be configured to heat asubstrate, and withstand temperatures, of greater than or about 200° C.,and may be configured to heat a substrate and withstand temperatures ofgreater than or about 250° C., greater than or about 300° C., greaterthan or about 350° C., greater than or about 400° C., greater than orabout 450° C., greater than or about 500° C., greater than or about 550°C., greater than or about 600° C., greater than or about 650° C.,greater than or about 700° C., or higher. While many conventionalpedestals using an embedded resistive heater cannot operate to thesetemperatures, or may receive coupling breakdown that can decouple orwarp components, the present technology may be configured to operatesafely within these ranges without performance or structuraldegradation.

FIG. 6 shows a partial cross-sectional view of substrate supportassembly 400 according to some embodiments of the present technology.The figure illustrates heater plate 415 and stem 410, and provides viewsof the connections of second RF rod 435 and thermocouple 440 as thecomponents may terminate within the substrate support. The figure mayadditionally illustrate chucking capability, such as through vacuumconnections 445, which may allow clamping a substrate or wafer onto thesubstrate support. Additionally, as previously discussed, the substratesupport assembly may include an electrode 450 embedded within the heaterplate at a depth from the substrate support surface 407. Electrode 450may operate as an RF electrode by which an RF bias plasma may begenerated in a volume of space above the substrate support surface, andmay be within an envelope created between the substrate support surfaceand another electrode, such as a gas distribution assembly or faceplateas previously described. By providing vertical translation capability ofthe pedestal, which may be relative to a fixed faceplate, for example,the plasma window may be modified providing greater control of theformed plasma. The electrode 450 may be or include conductive materials,such as copper, tungsten, aluminum, or other materials in any number ofform factors including a mesh, filament, or other configuration. Theelectrode 450 may operate as both the electrode for generating an RFbias as well as a resistive element that may receive a current andgenerate heat to control temperature of the plate 415.

Electrode 450 may be embedded within the heating plate 415 in someembodiments, and may be embedded at a depth within the component. Forexample, in some embodiments the electrode 450 may be embedded at adepth of less than or about 5 mm within a ceramic heater plate of thesubstrate support assembly. In some embodiments the electrode may beembedded closer to the surface, and may be embedded at a depth in theheater plate of less than or about 4 mm, less than or about 3 mm, lessthan or about 2 mm, less than or about 1 mm, less than or about 0.5 mmor less. By embedding the electrode near the top surface, such as thesubstrate support surface, less distance may be added between theelectrode and an opposing electrode, and the substrate may be positionedcloser to the electrode.

The heater plate may also include one or more coatings to limit orreduce one or both of corrosion and erosion. Because some of the etchingmay include both a physical process and a chemical process, thesubstrate support, along with the substrate, may be exposed to botherosive plasma components, as well as corrosive chemical etchants. Thus,the ceramic may be coated with one or more materials to protect againstthese materials. The coating may include either a material to limitcorrosion or a material to limit erosion. In some embodiments a hybridcoating may be used, which may include a first layer and a second layer,although it is to be understood that either layer may be formed alone onsubstrate supports according to some embodiments of the presenttechnology.

For example, a first layer of a hybrid coating may extend conformallyacross the substrate support. The first layer may be a corrosionresistant layer, configured to protect the substrate support fromreactive etchants, including halogen-containing effluents or etchantmaterials. The first layer may be or include an anodization, electrolessnickel plating, aluminum oxide, or barium titanate in embodiments. Dueto the formation process for corrosion resistant coatings, completecoverage of the substrate support 405 may be achieved. A second layer ofthe hybrid coating, which may be a single coating on the substrate, mayalso be included externally to the first layer. The second layer mayinclude yttrium oxide, or other high performance materials, such ase-beam coating or yttrium oxide including aluminum, zirconium, or othermaterials.

As previously explained, RF match 420 may be used to provide both RFpower and AC current to the electrode 450. When both are deliveredtogether, interference may be produced. Accordingly, RF match 420 mayinclude a filter configured to reduce interference. The remainingfigures will describe variations on RF match 420. FIG. 7 illustrates aview of an RF match 700 according to some embodiments of the presenttechnology. The RF match may include a housing 705 in which multiplecomponents may be disposed. Housing 705 may include a number of inputports, which may include an RF power input 710, and an AC power input715. The RF match may have a divider 720 positioned between the twoinlets, and which may maintain separation along the RF match up througha window formed through the divider proximate the terminal connections,such as where the first RF rod may extend from a sidewall of the RFmatch, such as through the back of the device as illustrated.

From RF inlet 710, where an RF power source may be coupled with the RFmatch, may run an RF strap 725, which may be or include any of thematerials previously described, such as copper, for example. RF strap725 may extend to a primary coupling 730, which may be a couplingbetween the RF match 700 and the pedestal, such as where the first RFrod may extend. From AC inlet 715 may be run wiring 735 coupling the ACpower source to an RF filter 740. Wiring 745 may then extend from thefilter to the primary coupling 730. Accordingly, primary coupling 730may connect both the RF power and the AC power to the RF rod, where thepower may be delivered to the electrode embedded within the substratesupport.

RF filter 740 may include an inductor and a capacitor together in thefilter, including a set of inductors and capacitors. The components ofthe filter may operate to limit RF choking, or RF interference duringoperation. As illustrated in the figure, the inductor 742 may be a donutshape, and may be a ferrite core about which a number of windings may bemade, such as for each inductor. The ferrite may be manganese-zinc ornickel-zinc iron (III) oxide. The inductor may operate to provide atleast about 2 μH of inductance, which may confine an induced magneticfield, and limit eddy currents in the device. The capacitors may extendas a path to ground and may provide greater than or about 0.005 μF ofcapacitance. The filter of FIG. 7 may provide lower efficiencyfiltering, and depending on the operating RF power, the filter may belimited in the interference reduction. Accordingly, additionalconfigurations may be used to increase the inductance.

FIG. 8 illustrates a view of an RF match 800 according to someembodiments of the present technology. RF match 800 may include many ofthe components of RF match 700, and may include any of the componentsand materials described above. For example, RF match 800 may include RFinput 810, AC input 815, divider 820, and primary coupling 830. RF match800 may also include a filter 840, which may include a set of inductorsand capacitors. Inductors 842 may include a number of additional turnsof the inductors, and may include a cylindrical design. The inductorsmay provide over 10 μH of inductance, and the capacitors may providegreater than 0.01 μF of capacitance. The design of FIG. 8 may increasethe filtering efficiency at operating conditions, and may improve oninterference reductions.

FIG. 9 illustrates a view of an RF match 900 according to someembodiments of the present technology. RF match 900 may include many ofthe components of RF match 700 and 800, and may include any of thecomponents and materials described above. In some embodiments, RF match900 may include the inductors of both RF match 700 and RF match 800. Forexample, RF match 900 may include RF input 910, AC input 915, divider920, and primary coupling 930. RF filter 900 may also include a filter940, which may include a set of initial inductors 942, which may besimilar to the inductors of RF match 800. The RF filter 900 may theninclude a ferrite core 944, which may provide further inductance. Thefilter may provide greater than or about 20 μH of inductance, and thecapacitors may provide greater than or about 0.02 μF of capacitance.

Semiconductor processing systems according to some embodiments of thepresent technology may also be operated with a pulsing RF power, whichmay be provided by the RF match. Pulsing may provide increased controlover the plasma characteristics. In some embodiments where a remoteplasma may be formed in one portion of the chamber, and a local plasmamay be formed in a volume above the chamber, stepped RF pulsing may beperformed to control ion energy and radical density.

As previously explained, some etching operations may include forming adamaging inert plasma locally with an RF bias plasma, which may producemodified surfaces. These surfaces may then be removed with reactivechemicals formed in a remote plasma region. Accordingly, themodification operation may be performed with ion bombardment, while ionsmay be removed from the radical etchants formed in the remote plasmaregion in some embodiments. Adjusting the on and off pulsing, such asadjusting the duty cycle or pulsing frequency, may allow tuning of theetchant materials. This may allow control over the ratio of ions andradicals. These changes may be performed with synchronized ornon-synchronized pulsing. Hence, for additional ion development, pulsingof the RF bias plasma may include longer on cycles, and for increasedetchant radicals, pulsing of the remote plasma may include longer oncycles. These and any other variations on pulsing may be performed inchambers according to embodiments of the present technology. Byimproving the RF match and path delivery, the present technology mayallow more stable plasmas at lower operating powers, which may provideimproved fine tune etching of semiconductor features.

In the preceding description, for the purposes of explanation, numerousdetails have been set forth in order to provide an understanding ofvarious embodiments of the present technology. It will be apparent toone skilled in the art, however, that certain embodiments may bepracticed without some of these details, or with additional details.

Having disclosed several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of thedisclosed embodiments. Additionally, a number of well-known processesand elements have not been described in order to avoid unnecessarilyobscuring the present technology. Accordingly, the above descriptionshould not be taken as limiting the scope of the technology.

Where a range of values is provided, it is understood that eachintervening value, to the smallest fraction of the unit of the lowerlimit, unless the context clearly dictates otherwise, between the upperand lower limits of that range is also specifically disclosed. Eachsmaller range between any stated value or intervening value in a statedrange and any other stated or intervening value in that stated range isencompassed. The upper and lower limits of those smaller ranges mayindependently be included or excluded in the range, and each range whereeither, neither, or both limits are included in the smaller ranges isalso encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural references unless the context clearly dictatesotherwise. Thus, for example, reference to “a material” includes aplurality of such materials, and reference to “the channel” includesreference to one or more channels and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise”, “comprising”, “contains”, “containing”,“include”, “including”, and “includes”, when used in this specificationand in the following claims, are intended to specify the presence ofstated features, integers, components, or steps, but they do notpreclude the presence or addition of one or more other features,integers, components, steps, acts, or groups.

What is claimed is:
 1. A semiconductor processing system comprising: asubstrate support assembly having a substrate support surface, thesubstrate support assembly comprising: a ceramic heater defining thesubstrate support surface; a ground plate on which the ceramic heater isseated; a stem with which the ground plate is coupled; an AC powersource; an RF power source; an electrode embedded within the ceramicheater at a depth from the substrate support surface; and an RF matchcomprising a first input for the AC power source and a second input forthe RF power source configured to provide an AC current and an RF powerthrough the stem to the electrode, wherein the RF match comprises adivider between the first input and the second input, wherein the RFmatch is coupled with the substrate support assembly along the stem, andwherein the substrate support assembly and RF match are verticallytranslatable within the semiconductor processing system.
 2. Thesemiconductor processing system of claim 1, wherein the depth from thesubstrate support surface at which the electrode is embedded in theceramic heater is less than or about 5 mm.
 3. The semiconductorprocessing system of claim 1, wherein the substrate support assembly isconfigured to heat a substrate to a temperature greater than or about200° C.
 4. The semiconductor processing system of claim 1, wherein thesubstrate support surface is coated with a plasma resistant materialcomprising yttrium oxide.
 5. The semiconductor processing system ofclaim 1, further comprising an RF rod extending between the RF match andthe substrate support assembly.
 6. The semiconductor processing systemof claim 5, further comprising a second RF rod positioned within aceramic shaft disposed within the stem and diffusion bonded with theceramic heater.
 7. The semiconductor processing system of claim 5,wherein the substrate support assembly comprises fewer than tencouplings between the RF rod and the electrode.
 8. The semiconductorprocessing system of claim 5, wherein the RF match includes an RF strapcoupling an RF power source with the RF rod.
 9. The semiconductorprocessing system of claim 5, wherein the RF match includes an RF filtercoupling the AC power source with the RF rod.
 10. The semiconductorprocessing system of claim 9, wherein the RF filter comprises aninductor and a capacitor.
 11. The semiconductor processing system ofclaim 10, wherein the inductor comprises a ferrite core.
 12. Thesemiconductor processing system of claim 10, wherein the inductorprovides at least 2 μH.
 13. The semiconductor processing system of claim1, wherein the RF match is configured to provide a pulsing RF power, andwherein the electrode is configured to generate an RF bias plasma in avolume within the semiconductor processing system above the substratesupport assembly.
 14. A substrate support assembly having a substratesupport surface, the substrate support assembly comprising: a ceramicheater defining the substrate support surface; a resistive heatingelement embedded within the ceramic heater; a ground plate on which theceramic heater is seated; a stem with which the ground plate is coupled;an electrode embedded within the ceramic heater at a depth from thesubstrate support surface, wherein the electrode is configured togenerate an RF bias plasma in a volume above the substrate supportassembly; and an RF match configured to provide an AC current to theresistive heating element and an RF power to the electrode through thestem to the electrode.
 15. The substrate support assembly of claim 14,wherein the RF match is configured to provide a plasma power of below orabout 100 W to the electrode.
 16. The substrate support assembly ofclaim 14, wherein the RF match includes an RF strap coupling an RF powersource with an RF rod extending between the RF match and the substratesupport assembly.
 17. The substrate support assembly of claim 16,wherein the RF match includes an RF filter coupling an AC power sourcewith the RF rod.
 18. The substrate support assembly of claim 17, whereinthe RF filter comprises an inductor and a capacitor.
 19. The substratesupport assembly of claim 14, wherein the substrate support assembly isconfigured to heat a substrate to a temperature greater than or about400° C.
 20. A semiconductor processing system comprising: a substratesupport assembly having a substrate support surface, the substratesupport assembly comprising: a ceramic heater defining the substratesupport surface; a ground plate on which the ceramic heater is seated; astem with which the ground plate is coupled; an electrode embeddedwithin the ceramic heater at a depth from the substrate support surface,wherein the electrode is configured to generate an RF bias plasma in avolume above the substrate support assembly; and an RF match configuredto provide an AC current to the electrode to resistively heat theelectrode and an RF power through the stem to the electrode, wherein theRF match is coupled with the substrate support assembly along the stem,wherein the RF match is configured to provide a plasma power of below orabout 50 W to the electrode, wherein electrical couplings between the RFmatch and the electrode are characterized by losses in operation of lessthan or about 1 W, and wherein the substrate support assembly and RFmatch are vertically translatable within the semiconductor processingsystem.